Injector Pump Question

[ikoinu]

History:
-Have had HMMWV for about 6 years, ran fine (with repairs and maintenance). Did not start it for almost 2 months. Vehicle had 1/4 tank of older fuel. Will not start now.

Current symptoms:
-No fuel expelling from exhaust on cranking. Not starting.
Note: Glow plugs working normally, new batterys installed.

Actions taken:
-Tank drained and dropped. Fuel sock replaced. Fuel level sender replaced. Tank cleaned (newer tank, not particularly dirty). Tank filled to 1/3rd.
-Fuel filter drain checked, fuel comes out.
-Fuel filter outlet hose to injection pump checked, pumps fuel normally.
-Injection pump return hose checked, flows while cranking.
-2 Injection pump outlet lines checked, barely flows at all.
-Multiple injectors cracked, barely flows at all.
-Tested 2 solenoid connectors on injection pump with ignition on, front wire shows 20+ volts and other wire appears to be ground.

Originally thought that the fuel level had gone too low or vehicle was not used long enough so it must have lost prime.
Fuel seems to be making it to the IP, but is not flowing out to the injectors (even if cracked).

Question:
Should both leads connected to the solenoid on top of the injector pump be positive at 24v when the ignition is turned on, or is one a negative lead? (Smart box issue?)

Note: I marked what I'm seeing for both connectors at my solenoid on a page from the manual.

 

[ikoinu]

I've tried pressurizing the tank a little while cranking to get fuel up to the IP, which appears to work.
Now I'm trying to decide whether all injectors need to be cracked to expel air (tough accessing some of them), or if the solenoid is possibly the culprit.

 

[Dieselmeister]

Pull a glow plug and see if it is wet with diesel. Are your plugs working? I doubt it's the fuel quality, unless it has water in it. If it resembles diesel, it will most likely work, even if it's old. If your IP is working, you will get about a drop when you crack the line and crank the engine. Remember, this is being injected into the engine at high pressure so it is a very small, metered quantity. Don't expect to see diesel "flowing" out of the injector lines.

 

[ikoinu]

Pull a glow plug and see if it is wet with diesel. Are your plugs working? I doubt it's the fuel quality, unless it has water in it. If it resembles diesel, it will most likely work, even if it's old. If your IP is working, you will get about a drop when you crack the line and crank the engine. Remember, this is being injected into the engine at high pressure so it is a very small, metered quantity. Don't expect to see diesel "flowing" out of the injector lines.

Plugs are fully functional. Installed a momentary manual system due to dumb box malfunction a while back. Everything worked fine for a number of years. When the glow plugs were not working before there was a strong fuel vapor emitted from the exhaust after cranking for a bit. There is no fuel coming from the tailpipe now.
Thinking about pulling all glow plugs as a way to check that cylinders are receiving fuel.

 

[thompsoncustom]

I've tried pressurizing the tank a little while cranking to get fuel up to the IP, which appears to work.
Now I'm trying to decide whether all injectors need to be cracked to expel air (tough accessing some of them), or if the solenoid is possibly the culprit.

pressurizing the tank and then crack all the injectors one by one to bleed off any air sounds like a good idea to me. If you can get it started then and it runs like crap you may have to bleed them some more.

 

[Milcommoguy]

History:
-Have had HMMWV for about 6 years, ran fine (with repairs and maintenance). Did not start it for almost 2 months. Vehicle had 1/4 tank of older fuel. Will not start now.

Current symptoms:
-No fuel expelling from exhaust on cranking. Not starting.
Note: Glow plugs working normally, new batterys installed.

Actions taken:
-Tank drained and dropped. Fuel sock replaced. Fuel level sender replaced. Tank cleaned (newer tank, not particularly dirty). Tank filled to 1/3rd.
-Fuel filter drain checked, fuel comes out.
-Fuel filter outlet hose to injection pump checked, pumps fuel normally.
-Injection pump return hose checked, flows while cranking.
-2 Injection pump outlet lines checked, barely flows at all.
-Multiple injectors cracked, barely flows at all.
-Tested 2 solenoid connectors on injection pump with ignition on, front wire shows 20+ volts and other wire appears to be ground.

Originally thought that the fuel level had gone too low or vehicle was not used long enough so it must have lost prime.
Fuel seems to be making it to the IP, but is not flowing out to the injectors (even if cracked).

Question:
Should both leads connected to the solenoid on top of the injector pump be positive at 24v when the ignition is turned on, or is one a negative lead? (Smart box issue?)

++++++++++++++++++++++++++++++++++
Peeking over your shoulder...

Parked for a couple of month ?
Older fuel ?

Will not start now. IMO this can be something to consider. The bio-mixed diesel with 5-25% crap, low sulfur, lubricants and any water (there is some water ) to make a blend of a biological mix to harbor the dreaded DIESEL BUG. The filter/s can catch the big parts, But the little ones are flowing, modifying the fuel. It can smell funny and it will gum up the IP metering valve. This is a small and precision, controlling fuel deliver and shut off. If stuck one is... rhymes with ________ed.

You stated voltage. All things correct and normal, 20 volts (a bit low, double check test / batteries) should pull in the shut off solenoid allowing the metering valve to open (run) and fuel to flow when cranking engine over. Also the other connector at the rear is the cold advance. It will have 24 volts when engine is a first time start or cold.

Opening a injector hardline one would expect to have a very small amount of fuel showing up, small. ( I place a clean white rag between injector and hardline feed. After cranking five or six times should have a 2-3 inch blotch spot, not much but noticeable. Not a flow, no squirting.

IMO Stated fuel flowing with some pressure? towards IP input. There is a input filter, But it would and could be clogged up, to be considered, but not likely with quality filtering down stream. What kinda run time on IP ?? abuse, worn out tired?

Not a start box issue. Famous for all problems HumV, ask me. Having the voltage to the IP shut off solenoid AND hearing the clicking test and IP hasn't been jacked with, working before? OK.

MY guess is pointing too, but could be, maybe, inline with crap fuel and not driven enough to keep free from the "dreaded diesel bug."

Think of it like Covid for the HumV. Google search DB2 pump and operation. Diesel fuel storage and additives and medicine for the BUG. Biocide.

YMMV, CAMO

 

[ikoinu]

pressurizing the tank and then crack all the injectors one by one to bleed off any air sounds like a good idea to me. If you can get it started then and it runs like crap you may have to bleed them some more.

Thanks. Was just trying to figure out if there was another obvious issue so I wasn't pissing in the wind cracking injectors (some of them are a right PITA to get to).
Time to start pissing in the wind

 

[Mogman]

Thanks. Was just trying to figure out if there was another obvious issue so I wasn't pissing in the wind cracking injectors (some of them are a right PITA to get to).
Time to start pissing in the wind

If you disconnect and connect the wire #54 at the front of the IP do you hear the solenoid click inside the IP?
The other wire is the cold advance, working or not the engine should still start.
Just keep trying, sometimes the plungers in the IP get stuck, good hot batteries and a fast cranking speed are your friend as the more pressure the transfer pump in the IP can make the better the odds your will move the plungers in the IP.

 

[ikoinu]

Milcommoguy, the metering valve is clicking and getting 20+ volts, do you think it could still be clogged up? Should I pull it and run it through a sonic cleaner?

Not sure on IP run time. The vehicle is an 88, I put 16k on it myself for a grand total of 32k on the odometer (this odometer at least Purchased from a dealer who got it from the auction and ran it for a while, mileage is legit on the civilian side but who knows about the military. Was starting and running great until it stopped. Diesel was almost 4 years old, but is pushing hard out of the water separator so good flow.

When something is wrong I always look suspiciously at the stupid-box, but you're right this is definitely a fuel flow issue.

Will do.

 

[ikoinu]

If you disconnect and connect the wire #54 at the front of the IP do you hear the solenoid click inside the IP?
The other wire is the cold advance, working or not the engine should still start.
Just keep trying, sometimes the plungers in the IP get stuck, good hot batteries and a fast cranking speed are your friend as the more pressure the transfer pump in the IP can make the better the odds your will move the plungers in the IP.

Did not try disconnecting and reconnecting #54 (front wire on the IP). Had felt it when the ignition is turned on and off and it does click. Should be good?

 

[Mogman]

Did not try disconnecting and reconnecting #54 (front wire on the IP). Had felt it when the ignition is turned on and off and it does click. Should be good?

That should be OK.
You never said you replaced the filter, it is of utmost importance to maintain a very clean filter or the lift pump can push crap past the filter and plug up the IP.
I never cared for canister filters, when I started as a mechanic many types of equipment and autos had canister filters, there is a reason they have fallen out of favor, even IF they are correctly assembled which happens much less that one would think, if they get plugged they have a tendency to allow trash to go around the end seals.
This is not so with spin on filters unless they have a by-pass valve.

If your filter is not complete including the water separator then it will not seal off the end seals at all.
You cannot clean the IP in a sonic cleaner, it is much too complex for that to work.

 

[Milcommoguy]

Milcommoguy, the metering valve is clicking and getting 20+ volts, do you think it could still be clogged up? Should I pull it and run it through a sonic cleaner?

Not sure on IP run time. The vehicle is an 88, I put 16k on it myself for a grand total of 32k on the odometer (this odometer at least Purchased from a dealer who got it from the auction and ran it for a while, mileage is legit on the civilian side but who knows about the military. Was starting and running great until it stopped. Diesel was almost 4 years old, but is pushing hard out of the water separator so good flow.

When something is wrong I always look suspiciously at the stupid-box, but you're right this is definitely a fuel flow issue.

Will do.

Click is solenoid pulling in. Doesn't mean metering valve is free.
Study the DB2 pump operation > https://media.defense.gov/2014/Jun/20/2002655917/-1/-1/1/140620-N-ZZ182-6558.pdf

There could be one or a chain of little issues to resolve any problem. Poking around for a quick fix might not happen. Follow the fuel with logical steps like you have. Process of elimination, test and next step. Got fuel to the pump? Next, want fuel out? Sounds simple enough. IP is a complicated, precision device.

Hearing of 4 year old California fuel raises my ears. Did truck run... hick up and stop? Red herrings and rabbit hole testing on anything, likely won't get good results. Adds to the story... so turn the page. Old fuel, pushing out hard says lift pump is working.

A little more digging deep, Tiger. HumV's don't have feelings. SO use logic. I am pointing a finger to the IP. That's my guess from the text. LOL

SO... What's really in your tank? CAMO